GCN Circular 18861
Subject
GRB 160113A: Fermi GBM detection
Date
2016-01-14T00:57:55Z (9 years ago)
From
Eric Burns at U of Alabama <eb0016@uah.edu>
O.J. Roberts (UCD) and E. Burns(UAH)
report on behalf of the Fermi GBM Team:
"At 09:32:30.52 UT on 13 January 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160113A (trigger 474370354 / 160113398).
The on-ground calculated location, using the GBM trigger
data, is RA = 187.3, DEC = 11.5, with an uncertainty
of 1.2 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).
All of the optically variable sources detected by iPTF (Singer, GCN 18859)
are contained in the uncertainty region surrounding the final location.
The angle from the Fermi LAT boresight at the GBM trigger time is 98
degrees.
The GBM light curve consists of a smaller peak between
T-5 and T+10 followed by a bright peak from T+20 to about T+60
with a duration (T90) of about 25 s (50-300 keV).
The time-averaged spectrum from T0+25.60 s to T0+51.20 s is
best fit by a Band function with Epeak = 98 +/- 1 keV,
alpha = -0.40 +/- 0.03, and beta = -3.16 +/- 0.11
The event fluence (10-1000 keV) in this time interval is
(3.12 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+31.51 s in the 10-1000 keV band
is 27.7 +/- 0.5 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."